Bug 41662: Disable about:sync-logs

Even though we disable sync by default with
`identity.fxaccounts.enabled`, this about: page is still avilable.
We could throw an exception on the constructor of the related
component, but it would result only in an error in the console, without
a visible "this address does not look right" error page.
If we fix the issues with MOZ_SERVICES_SYNC, we can restore the
component.

services/sync/components.conf

@@ -11,10 +11,4 @@ Classes = [
         'esModule': 'resource://services-sync/Weave.sys.mjs',
         'constructor': 'WeaveService',
     },
-    {
-        'cid': '{d28f8a0b-95da-48f4-b712-caf37097be41}',
-        'contract_ids': ['@mozilla.org/network/protocol/about;1?what=sync-log'],
-        'esModule': 'resource://services-sync/Weave.sys.mjs',
-        'constructor': 'AboutWeaveLog',
-    },
 ]